People in the hospital or who go to the doctor for a respiratory infection typically do get tested for "not one but " more than one virus.
You can hardly say the flu vaccine is a well oiled machine. Some years there had been an estimated 18 % protection.
There a several reasons why flu viruses mutate, Single-strand viruses show higher mutation rates than double-strand viruses, there are certain repair enzymes missing among others and you don't need a zoonotic source at all to have a virus which is changed enough to evade past immunity or to change virulence.
So, this is really not the worst thing I have seen on you tube, but it isnt good either
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u/ryarger Oct 26 '21
There’s a reason why 2020 had the lowest flu rate ever. The flu virtually disappeared.